Just wondering.. I have 2 questions

I stopped birth control pills a week or so ago been on them since I was 13.

1. What has everyone heard about Birth control pills? I stopped them because I was scared for infertility.

2. I’ve been staying tired, had a period 4 days ago but only lasted 2 days now I’m hurting in my stomach and side bad. Not wanting to eat much, bad acid reflux. What could this be?